Articles containing a matrix material and plurality of copper nanoparticles in the matrix material that have been at least partially fused together are described. The copper nanoparticles are less than about 20 nm in size. Copper nanoparticles of this size become fused together at temperatures and pressures that are much lower than that of bulk copper. In general, the fusion temperatures decrease with increasing applied pressure and lowering of the size of the copper nanoparticles. The size of the copper nanoparticles can be varied by adjusting reaction conditions including, for example, surfactant systems, addition rates, and temperatures. Copper nanoparticles that have been at least partially fused together can form a thermally conductive percolation pathway in the matrix material.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method comprising: providing a plurality of copper nanoparticles; wherein the plurality of copper nanoparticles are less than about 20 nm in size; mixing the plurality of copper nanoparticles with a matrix material; and applying pressure to at least partially fuse the plurality of copper nanoparticles together to form a nanoparticle network that remains disposed in the matrix material, wherein applying pressure comprises press molding a mixture of copper nanoparticles and the matrix material.
2. The method of claim 1 , wherein the plurality of copper nanoparticles further comprise a surfactant system.
3. The method of claim 2 , wherein the surfactant system comprises a bidentate diamine and one or more C6-C18 alkylamines.
4. The method of claim 1 , wherein the plurality of copper nanoparticles range between about 1 nm and about 10 nm in size.
5. The method of claim 1 , wherein the plurality of copper nanoparticles range between about 1 nm and about 5 nm in size.
6. The method of claim 1 , further comprising: curing the matrix material.
7. The method of claim 1 , wherein the matrix material is selected from the group consisting of a polymer matrix, a rubber matrix, a glass matrix, a ceramic matrix and a metal matrix.
8. The method of claim 1 , further comprising: applying heat to at least partially fuse the plurality of copper nanoparticles together to form the nanoparticle network.
9. The method of claim 1 , wherein the nanoparticle network defines an electrically conductive percolation pathway in the matrix material.
10. A method comprising: providing a plurality of copper nanoparticles; wherein the plurality of copper nanoparticles are less than about 20 nm in size; mixing the plurality of copper nanoparticles with a matrix material; and applying pressure to at least partially fuse the plurality of copper nanoparticles together to form a nanoparticle network; wherein applying pressure comprises extruding a mixture of copper nanoparticles and the matrix material.
11. The method of claim 10 , wherein the plurality of copper nanoparticles further comprise a surfactant system.
12. The method of claim 10 , wherein the surfactant system comprises a bidentate diamine and one or more C6-C18 alkylamines.
13. The method of claim 10 , wherein the plurality of copper nanoparticles range between about 1 nm and about 10 nm in size.
14. The method of claim 10 , wherein the plurality of copper nanoparticles range between about 1 nm and about 5 nm in size.
15. The method of claim 10 , further comprising: curing the matrix material.
16. The method of claim 10 , wherein the matrix material is selected from the group consisting of a polymer matrix, a rubber matrix, a glass matrix, a ceramic matrix and a metal matrix.
17. The method of claim 10 , further comprising: applying heat to at least partially fuse the plurality of copper nanoparticles together to form the nanoparticle network.
18. The method of claim 10 , wherein the nanoparticle network defines an electrically conductive percolation pathway in the matrix material.
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April 20, 2015
October 24, 2017
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